Sebaceous Gland Carcinoma

What sebaceous carcinoma is

Sebaceous glands make sebum, the oil that lubricates skin and hair. The eyelids contain specialized oil glands: the meibomian glands in the tarsal plates and the glands of Zeis at the lash line. Most sebaceous carcinomas arise in these eyelid glands, especially the upper lid, which has more meibomian glands. About a quarter of cases occur elsewhere: face, scalp, neck, trunk or genitals.

It accounts for a small percentage of eyelid cancers in Western countries, after basal cell carcinoma and squamous cell carcinoma, but a higher share in Asian populations.

Symptoms

• A firm, painless, slowly growing lump in the eyelid, often yellowish
• Thickening of the eyelid, sometimes involving the whole lid
• Loss of eyelashes (madarosis) at the site
• Chronic redness, irritation or crusting of one eyelid, mimicking blepharitis or conjunctivitis
• A "chalazion" that keeps returning after treatment
• Ulceration or bleeding in later stages

Outside the eye, it appears as a yellowish or pink nodule that may bleed or crust.

Why it is often missed

Because chalazia are so common, ophthalmologists send tissue for pathology from recurrent or atypical "chalazia" in older adults. Unilateral, treatment-resistant blepharitis is another classic warning sign.

Risk factors

• Age over 60
• Female sex and Asian ancestry (eyelid tumors)
• Previous radiation to the head and neck, for example for childhood retinoblastoma or acne treatment in the past
• Weakened immune system, including organ transplant recipients and people with HIV
• Muir-Torre syndrome: a variant of Lynch syndrome in which sebaceous skin tumors occur alongside colorectal, endometrial, urinary tract and other cancers. Sebaceous tumors outside the eyelid are particularly suggestive.

Diagnosis

1. Examination of the eyelid with a slit lamp, flipping the lid to see the inner surface, and checking lymph nodes in front of the ear and in the neck.
2. Biopsy: a full-thickness eyelid biopsy shows the cancer cells with fatty (lipid) contents. Special stains help distinguish it from basal or squamous cell carcinoma.
3. Map biopsies of the conjunctiva, because this cancer can spread through the surface lining of the eye (pagetoid spread) beyond the visible lump.
4. Staging: CT, MRI or PET scans for larger tumors or suspicious lymph nodes. Sentinel lymph node biopsy is sometimes used.
5. Mismatch repair testing: the tumor is checked for the protein changes of Lynch syndrome. If abnormal, genetic counseling and germline testing follow, along with screening such as colonoscopy.

Treatment

• Surgery: wide local excision with frozen-section or Mohs micrographic surgery to confirm clear margins. The eyelid is then reconstructed by an oculoplastic surgeon.
• Cryotherapy or topical chemotherapy drops (such as mitomycin C) for spread across the conjunctiva.
• Orbital exenteration (removal of the eye and surrounding tissues) for tumors that have invaded the eye socket.
• Radiation therapy for people who cannot have surgery, after incomplete surgery, or for lymph node spread.
• Lymph node surgery and systemic treatment, including immunotherapy in research or advanced settings, when cancer has spread.

Outlook

Small tumors diagnosed early and fully removed have an excellent outlook. The cancer can recur locally, spread to lymph nodes in up to about a fifth of eyelid cases, and occasionally spread to distant organs. Tumor size over 10 mm, involvement of both eyelids, long delays in diagnosis and spread to the conjunctiva worsen the outlook. Long-term follow-up with regular eyelid and lymph node checks is needed, and people with Muir-Torre syndrome need lifelong cancer screening.

Frequently asked questions

What does sebaceous carcinoma of the eyelid look like?

It typically looks like a firm, painless, yellowish lump or a thickened area in the eyelid, often with missing lashes. It can also look like a long-lasting red, irritated or crusted eyelid on one side, similar to blepharitis.

How can you tell sebaceous carcinoma from a chalazion?

A chalazion usually improves within weeks with warm compresses and rarely recurs in the same place. Sebaceous carcinoma persists, grows, recurs after drainage, and often causes lash loss. Only a biopsy can confirm it, which is why recurrent chalazia in older adults are biopsied.

Is sebaceous carcinoma deadly?

It can be if found late, because it can spread to lymph nodes and other organs. When diagnosed early and fully removed, the outlook is very good. Prompt biopsy of persistent eyelid lumps is key.

What is Muir-Torre syndrome?

Muir-Torre syndrome is a form of Lynch syndrome, an inherited condition caused by faulty DNA repair genes. People with it develop sebaceous skin tumors along with cancers of the colon, uterus, urinary tract and other organs. A sebaceous carcinoma diagnosis often prompts testing for it.

Who is at risk of sebaceous gland carcinoma?

Risk is higher in adults over 60, women, people of Asian ancestry, those who have had radiation to the head or face, people with weakened immune systems, and people with Lynch or Muir-Torre syndrome.